For my investigation I am going to look at Reaction Times. Reaction time is the interval time between the presentation of a stimulus and the initiation of the muscular response to that stimulus.

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Introduction

Plan For my investigation I am going to look at Reaction Times. Reaction time is the interval time between the presentation of a stimulus and the initiation of the muscular response to that stimulus. A primary factor affecting a response is the number of possible stimuli, each requiring their own response, that are presented. Fingertip reaction time is tested by dropping a ruler between the outstretched fingers of the subject without warning. The distance fallen can be used to determine the time to react to the event. If there is only one possible response (simple reaction time) it will only take a short time to react. If there are several possible responses (choice reaction time) then it will take longer to determine which response to carry out. All living organisms are sensitive to the environment; this means they can detect changes in their environment these changes are known as stimuli. The parts of the body which detects the stimuli are called receptors. In animals they are known as the sense organs. My hypotheses are; 1. Reaction times are normally distributed 2. A person's dominant hand will always react faster 3. If a person is fast with one hand then they will also be fast with the other meaning that if they are ranked as one of the fastest with one hand then their other hand's reaction time will also will be one of the fastest. ...read more.

Middle

As I am measuring time my data is continuous. Therefore I must use grouped data. This will affect my analysis. For grouped data I can only state the class interval that contains the median. I will draw a cumulative frequency curve and calculate quartiles. To test my third hypothesis I will draw scatter graphs to see if there is a correlation between the speed in reaction time between one hand and the other. I will calculate the mean point and use this to draw a line of best fit and regression line. "Regression" is the process of finding the function satisfied by the points on the scatter diagram. I know that the points might not fit the function exactly but my aim is to get as close as possible. "Linear" means that the function we are looking for is a straight line (so our function f will be of the form y = ax + b for constants a and b). I expect the two to be positively correlated, meaning that if one person records a fast reaction time with their dominant hand, then they will be fast with the other hand, albeit not as fast, as I hope to prove from earlier tests. ...read more.

Conclusion

The results from this experiment had many errors occur due to humanly errors. Whilst doing the experiment we didn't measure the 10cm above the hand accurately. This caused all are results to be inaccurate also we decided we needed to be more careful when measuring the 10cm above people hand because they kept moving their hand as the ruler went up. Also we only when we did our preliminary experiment we only did the experiment 5times. This didn't give us a good range of results and caused the whole experiment to weaken. We noticed no adequate conclusion could be backed up with sufficient evidence as a suitable graph could not be formed. We also tried different measurements from the hand and came to the conclusion 10cm would be adequate. From the preliminary experiments we decided to do the experiment 10times so we could monitor the investigation closely. So in our real experiment we decided on 10cm from the hand and we would repeat it 10times. My data is primary data as I have collected it myself, I will use a stratified sample of 60 students from a range of year groups. Stratified sampling is when you divide your sample into different categories e.g. age or gender and then take a sample from each which is proportionate to the number in the overall population. ...read more.

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